Start by heating your large skillet over medium heat and adding the ground beef along with the diced onion. Break the meat apart with your spatula as it cooks so it browns evenly instead of clumping. This usually takes about seven to eight minutes, and you'll know it's ready once there's no pink left and the onion has softened.
Once the beef is browned, drain off any extra grease so your burritos aren't greasy inside. Stir in the cumin, oregano, chili powder, salt, and pepper, then pour in most of the tomato or enchilada sauce, saving a little for drizzling later. Let this simmer on low for about five minutes so the flavors soak into the meat.
While the beef simmers, add your refried beans to a small saucepan over medium-low heat. Stir in the cheddar cheese and keep stirring until it melts completely into the beans. This little step turns plain refried beans into something rich and creamy that makes a real difference in the final burrito.
Heat your tortillas in the microwave for about a minute so they're soft and pliable. Spread a thin layer of the cheesy beans down the center of each tortilla, then spoon some of the seasoned beef on top. Don't overfill them, or you'll struggle to roll them up neatly.
Fold in the ends of each tortilla, then roll it up snugly so the filling stays put. Place a couple of finished burritos on a microwave-safe plate, drizzle the reserved sauce over the top, and sprinkle on a little more cheddar. Microwave for about a minute, just until the cheese melts and the burritos are hot all the way through, then repeat with the rest.